a. The Field of the Invention
This invention is concerned with forming highly efficient markings on the surface of roadway areas to provide such areas with traffic regulating signs, such as traffic lane dividing lines, parking areas defining lines, pedestrian crossing signalling strips and so on.
This invention also relates to roadway areas provided with such markings.
b. The Prior Art
Markings and methods of their formation are well known. A number of patents strictly related this art have been heretofore issued. The problems involved in this art have been extensively discussed in my U.S. Pat. Nos. 4,069,281, and 4,146,635.
In the first Patent there has been described and claimed a method of forming nighttime visible markings on a roadway and in general, a roadway area pavement, this method comprising the steps of providing a lower base-forming layer to be subsequently applied to a roadway surface, applying a hardenable synthetic plastic material over said lower layer to form thereon an upper layer of such synthetic plastic material, embedding anti-skid particles in said upper layer prior to hardening of said synthetic plastic material, applying additional quantities of synthetic plastic material onto said upper layer at longitudinally spaced locations of the same and prior to hardening of the material thereof, so that each such additional quantity forms a protuberance on said upper layer, and cascading light-reflective particles over said protuberances prior to hardening of the synthetic plastic material thereof, so that upon subsequent hardening said reflective particles adhere to said protuberances.
There has been also described that the retro-reflective or retro-collimating particles or elements comprise a suitably reflectorised transparent body, that the upper layer is a traffic wear resisting layer consisting essentially of a high cohesion resin preferably selected from the group comprising polyurethane resin, polyamide resin and polyester resin, compatible with the said base and upper layer.
There has been further described and illustrated that the said retro-reflective (or retro-collimating) elements, appertaining to prior art, comprise globules the dimensions of which are largely greater than the thickness of the traffic wear resisting upper layer (U.S. Pat. No. 4,069,281, FIG. 11), which consists of a pigmented resin because the strip or another sign has the visibility as its primary object and therefore the sign must be sharply apparent on the roadway area pavement.
In the second patent there has been described and a marking comprising an impregnated, saturable layer permeated with a flexible tension resistant polymeric resin, which is partially impregnated by the composition of a primer layer and by the composition of the wear resistance upper layer. There has been further described a marking comprising a pigmented wear resistant composition which is substantially the same as the intermediate layer impregnating composition and an exceptionally thin pigmented wear resistant upper layer originated by the impregnation resin.
The most of the problems involved in the above described art can be assumed as having been satisfyingly solved. Certain problems are not completely solved namely problems related with costs and with some heretofore not technically superable limitation of the production rate, namely of the tape material of which the signs are to formed.